Field of the Invention
The present invention relates to an apparatus and method of controlling an electronic continuously variable valve timing (CVVT), and more particularly, to a sensor and a motor coupled to a reducer by using an electrical signal to adjust a timing of a cam shaft of a combustion engine.
Description of the Related Art
Typically, in automotive engineering, variable valve timing (VVT) control technology describes technology that adjusts timing for opening and closing a value abased on revolutions of a combustion engine. Since the VVT control technology adjusts a period of opening and closing a valve based on low-speed revolutions and high-speed revolutions of an engine, both fuel efficiency and an output of a vehicle is increased.
Generally, in engines a valve opening and closing timing is defined to obtain a maximum output in specific revolutions per minute (RPM) band. In other words, the valve opening and closing timing should extend for expansion and explosion of a mixer in a low RPM band, and in a high RPM band, the valve opening and closing timing should be shortened for emission of an exploded mixer. When a period of opening and closing a valve is adjusted to a low speed, emission of the mixer is later in a high RPM band. When the period of opening and closing the valve is adjusted to a high speed, compression of the mixer is later in a low RPM band, causing a reduction in efficiency of an engine. The VVT control technology has been proposed to solve the above mentioned limitations. The VVT control technology adjusts an opening and closing timing of a valve to match revolutions of an engine. Accordingly, a high fuel efficiency and a high output are simultaneously obtained at both a high speed and a low speed.
In particular, an operation of changing a VVT is performed at two stages for example, a low-speed rotation and a high-speed rotation. Recently, a CVVT-enabled CVVT system is being generalized. Additionally, the CVVT system may be named VVT, CVVT, CVTC, and VANOS. The CVVT system is a system that continuously adjusts an opening and closing timing of a valve according to revolutions of an engine and a degree to which an accelerator is opened. The CVVT system includes an interior chamber coupled to a cam shaft, an external system that coupled a timing system (e.g., a chain, a belt, etc.) and is configured to be supplied with power from an engine, a sensor configured to measure a current timing, and a control device. The control device includes a hydraulic type control and is equipped with an oil control valve (OCV). Recently, the control device includes a control device configured to adjust the performance of an electric motor to improve response characteristics of the motor.
In an electric motor control type CVVT system of the related art, an electronic control unit (ECU) of a vehicle receives revolutions of a cam shaft from the sensor disposed proximate to the cam shaft and receives revolutions of a crank shaft from a second senor disposed proximate to the crank shaft. The electric motor control type CVVT system is configured to calculate various control values to adjust an electric motor based on a result of the calculation. However, in the CVVT system of the relate art, an arithmetic operation to adjust the electric motor increases an operational load performed by the ECU and the arithmetic operation increases an operation error of the ECU and decreases a processing speed of the ECU. In particular, the first sensor disposed proximate to the cam shaft and the second senor disposed proximate to the crankshaft respectively transmit the revolutions of the cam shaft and the revolutions of the crank shaft to the ECU. The ECU is configured to perform an arithmetic operation on the revolutions of the cam shaft and the revolutions of the crank shaft. Additionally, the ECU is configured to calculate the various control values to adjust the electric motor. Therefore, signal delay occurs in a transmission process, and the signal delay decreases the processing speed of the ECU.
The matters disclosed in this section are merely for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgment or any form of suggestion that the matters form the related art already known to a person skilled in the art.